The uniformity of the microstructure of steel strip over the entire coil length (“intra-coil uniformity”) and between different coils of the same grade (“inter-coil uniformity”) is key to consistent material behaviour at steel manufacturers’ proprietary processes like rolling and customers’ processes like pressing and deep-drawing. Evidently, stable and consistent processes yield optimal product quality and maximize efficiency, giving minimal loss of material and energy over the entire production chain. The steel manufacturers already control the quality of their products by tensile testing and microstructure analysis of samples taken at the coil head or tail. Whereas this procedure yields data on the “inter-coil uniformity”, the “intra-coil uniformity” can be monitored and improved only using continuous product measurements over the full length of the strip. Since the microstructure of steel governs the electromagnetic and ultrasonic properties, practically all measurement techniques to monitor the microstructure online are based on sensing these properties. Despite many efforts however, the steel research community has not established unique and universal relationships between the online measured parameters and microstructure. In this perspective, the present proposal Product Uniformity Control (PUC) is not aiming for absolute prediction of microstructure parameters, but seeks for relative relationships in order to improve both “inter-coil” and “intra-coil” uniformity of steel strip. The PUC proposal follows an integrated research path of modelling, laboratory tests and dedicated plant trials to enhance the understanding of the relation between microstructure and online measured parameters. It also aims to understand and reduce cross-sensitivities of the sensor systems to measurement conditions like speed and lift-off. Finally, it investigates the quality and monetary benefits from application of continuous product uniformity monitoring in the steel industry.
Professor at Advanced Non-destructive Testing
San Sebastian, Spain
Birmingham, United Kingdom
Manchester, United Kingdom
Funding Chalmers participation during 2013–2017
Areas of Advance